Apparatus for continuous production of spiral pipe

ABSTRACT

A method and apparatus for continuously producing spiral pipe from sheet material including feeding a strip of the sheet material into a spiral pipe forming machine, continuously deforming a portion of the longitudinal edges of the sheet material so as to bend the edge downwardly toward the axis of the formed pipe and out of the normal plane of the sheet material, forming the sheet material into a spiral tube and bringing the deformed edges into parallel face to face abutting relationship, welding the edges into a seam, and reforming the deformed portion of the sheet material to provide a smooth forged weld.

o I Umted States Patent 1191 1111 3,776,448

Fay Dec. 4, 1973 54] APPARATUS FOR CONTINUOUS 3,358,112 12/1967 Timmers 2974773 x PRODUCTION OF SPIRAL PIPE 3,524,035 8/1970 Kelley 219/67 X [76] Inventor: g g gz gx bt g Nelson Primary Examiner-Richard B. Lazarus Attorney-Harold H. Dutton, Jr.

[22] Filed: Mar. 26, 1973 211 App]. No.: 344,607 57 ABSTRACT Related US. Application Data [62] Division of Ser. No. 107,748, Jan. 19, 1971, Pat. No.

[52] US. Cl. 228/5, 228/15, 228/17 [51] Int. Cl B23k 29/00 [58] Field of Search 228/4, 5, 15, 17, 228/49 [56] References Cited UNITED STATES PATENTS 3,287,536 11/1966 Fay 219/62 3,314,141 4/1967 Bacroix 29/477.3

A method and apparatus for continuously producing spiral pipe from sheet material including feeding a strip of the sheet material into a spiral pipe forming machine, continuously deforming a portion of the longitudinal edges of the sheet material so as to bend the edge downwardly toward the axis of the formed pipe and out of the normal plane of the sheet material, forming the sheet material into a spiral tube and bringing the deformed edges into parallel face to face abutting relationship, welding the edges into a seam, and reforming the deformed portion of the sheet material to provide a smooth forged weld.

14 Claims, 12 Drawing Figures PATENTEDUEC 4197s SHEET 1 [1F 3 PRIOR ART PATENTEUBEC 815 3,776,448

SHEET 20F 3 This is a division of application Ser. No. 107,748, filed Jan. 19, 1971 now U.S. Pat. No. 3,722,075.

This invention relates to a method and apparatus for continuously forming spiral pipe, and is an improvement over my US. Pat. No. 3,287,536, issued Nov. 22, 1966.

BACKGROUND AND OBJECTS Prior methods for continuously forming pipe have included the formation of straight-seam pipe by bending a substantially rectangular strip of sheet material into a cylindrical shape, and then securing the seam by welding or other edge joining techniques. Bending of the strip into a cylindrical shape has been accomplished by pushing or drawing the strip through a restrictive circular opening or die. Edge joining techniques previously used in the production of straight-seam pipe have included fusing edges together by first heating the edges with high frequency energy, moving into abutting relationship, and then applying forces in a direction substantially tangentially to the surface of the cylinder at the seam to accomplish a fusion of the heated edges. However, this method has not been readily acceptable for the formation of spiral-seam pipe.

In the operation of conventional spiral forming techniques, the edges of the sheet material contact one another in advance of the point where the spiral forming is completed. Since the sheet edges are heated to the plastic state prior to their contact point, the edges are subjected to a shearing action as they move relative to one another through the distance between where the initial contact is made, and where the final spiral formation is completed. The period of shearing action on the plastic edges prevents formation of a satisfactory joint at the seam.

When a sheet of material is bent so that the opposite edges of the sheet are brought together so as to form a tube, a V-shaped joint results at the juncture of the edges. When this joint is welded, a stronger bond occurs at the bottom of the V that at the top of the V, and the result is a weak joint unless the V is filled with a weldment. Since no metal is added in high frequency thermowelding, a weak joint results.

My prior patent, mentioned above, attempted to provide a stronger and more acceptable joint by narrowing the sheet width and simultaneously building up the material at the edges of the sheet, prior to the forming of the bond, however, the nature of the joint between the two edges has still been unsatisfactory for use with new high frequency thermowelding techniques.

Therefore, a primary object of this invention is to provide a method and apparatus for continuously forming spiral pipe.

Another ojbect of this invention is to provide a method and apparatus for forming spiral pipe having a strong helical seam. I

A further object of this invention is to provide a method and apparatus forforming spiral pipe from ei' ther-flat or corrugated sheet material.

Still another object of this invention is to provide a method and apparatus for forming spiral pipe wherein the sheet material used is deformed near the edges thereof prior to forged welding to permit a good seam joint.

Yet another object of this invention is to provide a method and apparatus for the production of spiral pipe which overcomes the disadvantages of prior art techniques.

Still another object of this invention is to provide a method and apparatus for the production of spiral seam pipe wherein the seam is produced by bringing the two edges of the sheet material together in parallel fact to face abutting contact by forging at the apex using high frequency current to produce a strong weld between the two edges.

These and other objects and advantages of this invention will become apparent when considered in light of the following description and claims when taken together with the drawings in which:

FIG. 1a through 1e schematically illustrates the prior art bonds utilized for the seams of spiral pipe;

FIG. 2 is a fragmentary plan view of the forging rolls utilized in the present invention;

FIG. 3 is a schematic illustration of an apparatus according to this invention for manufacturing spiral pipe from planar sheet material;

FIG. 4 is a schematic illustration of an apparatus according to this invention for the manufacture of spiral pipe from corrugated sheet material;

FIG. 5 is a sectional view of one embodiment of the method of this invention;

FIG. 6 is the schematic illustration of the forging rolls utilized with one embodiment of this invention;

FIG. 7 is a schematic illustration of an alternate embodiment of this invention;

FIG. 8 is a schematic illustration of another embodiment of this invention; and

FIG. 9 is a view similar to that of FIG. 6, but just prior to the point of forging;

I FIG. 10 is a sectional view along lines l0l0 of FIG. 3 and viewed in the direction of the arrows,

FIG. 11 is a transverse section of the pipe seen in FIG. 3; and

FIG. 12 is a fragmentary enlarged view at the point of juncture of the two edges of the sheet material.

With reference now to FIG. 1, of the drawings, various joints are illustrated which have been utilized as seam joints in the manufacture of welded pipe. At FIG. la, the two edges 10 and 12 of the sheet material are brought as shown in dotted lines. In this manner, the edges contact only at point 14 leaving a V-shaped recess 16 which must be filled with a weld material 18. However, if thermoweld techniques are utilized, no additional weld material is added, and hence a weak bond results.

FIG. lb illustrates the technique utilized in my prior US. Pat. No. 3,287,536 wherein the edges are first built up as indicated at 20 and then brought into contact. However, this necessitates grinding off the excess material in order to form a smooth seam.

FIG. 10 discloses a process wherein the edges 22 and 24 are brought together by forces acting in the direction of the arrows, however, this produces a shearing force on the fusion joint and thus weakens the joint.

FIG. 1d illustrates the manner wherein squared off edges are also brought together by a shearing force, and this too results in a shearing force acting upon the weld.

FIG. 1e illustrates a method wherein the edges are lapped prior to welding, however, this too has not resulted in a satisfactory joint inasmuch as it will be uneven, and not a smooth finished surface.

With reference now to FIG. 3, a substantially planar strip of sheet material 26 is fed first through a pair of rolls 28 and 30 on an axle 32. Rolls 28 and 30 form ribs 34 and 36 in the sheet material 26, and sheet material 26 is fed at an angle of from about 28 to about 45 with the axis of the pipe being formed. Ribs 34 are formed at or near the edges of sheet material 26 so long as the edge faces when positioned for welding, are in parallel relationship. With reference to FIG. 10, the ribs 34 and 36 are seen to be substantially U-shaped, however, other suitable configurations could be utilized. In the embodiments of FIGS. 3 and ribs or beads 34 and 36 are formed along each side of sheet material 26 to shrink the sheet material 26 width slightly to hold the edges parallel and spaced apart to apex 111 for forging as seen in FIG. 11, where forging rolls 42 and 44 restore the original sheet width by rolling the molten defonned edges. If the ribs or beads 34 and 36 are formed so as to deflect the edge faces of the sheet downwardly from the plane of the sheet as the sheet is formed into a tube 38, the two edges of sheet material 26 will then be seen to have their faces abut fully from top to bottom squarely in face-to-face relationship resulting in an even contact of the edges throughout the thickness of the sheet material 26. This relationship, prior to forging, will permit a very strong weld to be produced.

A suitable high frequency welding tool, having contacts 40 and provided with current in excess of 450,000 cycles, is utilized to make the weld at apex 111 as the edges of sheet material 26 pass through forging rolls 42, 44, 46, 48 as seen in FIGS. 3, 8 and 12. The rolls 42, 44, 46 and 48 cooperate in pairs so as to flatten out the ribs 34 and 36 at the forgong point or apex 111. These rolls are each separately insulated of a ceramic or the like material indicated at 112 in FIG. 2. Additionally, during the forming of the material 26 to the tube 38, a pair of circumferential squeeze rollers 50 and 52 exert a radially inward force upon the sheet material 26 at apex 111 so as to forge the edges of the sheet material 26 into contact. This also assists in providing a strong bond at the joint.

In this manner of first upsetting the edges of the sheet to reduce the sheet width before forge welding, the edges are brought into a parallel face-to-face abutting contact which permits an even, strong weld through the thickness of the sheet material.

In an alternate embodiment of this invention, my technique is utilized in the manufacture of spiral seam, corrugated pipe, wherein corrugated sheet material is fed at an angle to the axis of the tube being formed. With reference to FIG. 4, corrugated sheet material 54 is fed at an angle of from about 45 to about 85 with the axis of the pipe being formed. The sheet material 54 first passes through a pair of rolls 56 and 58 which serve to form a rib or upset the edge portion of the sheet material 54 in a manner similar to rolls 28 and 30 of FIG. 3. The pair of ribs 60 and 62 are formed by means of the rolls 56 and 58 at the valley or the ridge of sheet 54 edges. The sheet material is fed so as to bring the edges thereof into a spaced apart parallel contact for welding as by the high frequency welding contacts 64. Next, the sheet material 54 passes through a series of cooperating rolls 66, 68, 70 and 72 which correspond to rolls 42, 44, 46 and 48 of FIG. 3. Rolls 66, 68, 70 and 72, as seen in FIGS. 6, 7 and 9 are used to remove the deformed portions or ribs 60 and 62 for forging at the apex 113 to provide a smooth seam. FIG. 4 illustrates the use of a roller chain 74 which is secured as at 76 and 78, the chain being placed under tension and preferably in the valleys of the corrugations so as to exert an even, radially inward force upon the sheet material as it is being formed to bring the edges of the sheet material 54 to edge abutting contact. The chain 74 takes the place of rolls 50 and 52 of FIG. 3. Additionally, portions 107 and 108 of rolls 66, 68, and 72 serve to prevent the edges of sheet material 54 from being separated during forging.

With reference now to FIG. 5, it is seen that the spiral seam tube 80 may be formed by deforming only the one edge of a sheet to provide an upset portion 82. In this manner, the edges 84 and 86 are still in face-to-face edge abutting relationship and also provide a good weld for the tubing.

Referring now to FIG. 2, rolls 42, 44, 46 and 48 are seen in more detail. Rolls 42 and 44 are mounted on spindles 88 and 90 respectively on a support assembly 92, while rolls 46 and 48 are mounted on spindles 94 and 96 respectively on support assembly 98 and are all separately ceramic insulated as indicated at 112. Support assembly 92 includes a fluid inlet passage 100 connected to fluid passage 102, and support assembly 98 includes a fluid inlet passage 104 connected to fluid passage 106. Passages 100 and 102 supply a cooling fluid to rolls 42 and 44, while passage 104 and 106 supply a cooling fluid to rolls 46 and 48. This cooling has been found to be necessary when using thermoweld techniques because of the high heat to which the rolls are subjected, to prevent damage to the rolls. Also each of the rolls must have the ceramic electrical insulation 112 to prevent an electrical short between the rolls.

It should be noted that the edges of the sheet material are very rapidly forced together, usually in a distance of travel of one-fourth inch and this occurs at the point of highest energy concentration to prevent freezing of the metal before the weld takes place.

While this invention has been described, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses and/or adaptations of the invention following in general, the principle of the invention and including such departures from the present disclosure as come within known or customery practice in the art to which the invention pertains, and as may be applied to the essential features hereinbefore set forth, as fall within the scope of the invention or the limits of the appended claims.

What is claimed is:

1. An apparatus for continusouly producing spiral pipe from sheet material having longitudinal side edges having faces which are perpendicular to the plane of the sheet including:

a. means for continuously deforming portions of said sheet material adjacent said longitudinal side edges thereof so as to bend said side edges downwardly toward the axis of the formed pipe and out of the normal plane of said sheet material,

b. means for feeding said sheet material at an angle to the axis of the formed pipe,

0. means for forming said sheet material into a spiral tube with said longitudinal side edges in parallel planes being moved into face to face abutting relationship,

d. means for welding said abutting longitudinal edges into a seam, and

e. means for reforming said deformed portions of said sheet material for providing a smooth continuous uninterrupted weld area.

2. An apparatus as in claim 1 and wherein:

a. said deforming means includes a roll couple.

3. An apparatus as in claim 2 and wherein:

a. said roll couple deforms said portions of said sheet by forming a rib therein.

4. An apparatus as in claim 3 and wherein:

a. said reforming means includes means for collapsing said rib.

5. An apparatus as in claim 4 and wherein:

a. said collapsing means includes a pair of cooperating roll members.

6. An apparatus as in claim 5 and including:

a. means for applying a radial squeezing force to said sheet material cooperatively with said forming means.

7. An apparatus as in claim 6 and wherein:

a. said deforming means is operative to deform each longitudinal side edge os said sheet material substantially simultaneously.

8. An apparatus as in claim 7 and wherein:

a. each of said roll members comprises a first and a second roll positioned inside of said spiral tube, and

b. a third and a fourth roll positioned outside of said spiral tube.

9. An apparatus as in claim 8 and wherein:

a. said first roll cooperates with one of said third and fourth rolls for collapsing one of said ribs, and

b. said second roll cooperates with the other of said third and fourth rolls for collapsing the other of said ribs. 7

10. An apparatus as in claim 9 and wherein:

a. said first, second, third and fourth rolls are water cooled.

11. An apparatus as in claim 9 and wherein:

a. said sheet material is substantially planar, and

b. said angle is from about 28 to about 45.

12. An apparatus as in claim 11 and wherein:

a. said radial squeezing force applying means includes a pair of rolls, and

b. each of said rolls acting on said spiral tube at substantially diametrically opposed positions.

13. An apparatus as in claim 9 and wherein:

a. said sheet material is corrugated, and

b. said angle is from about 45 to about 14. An apparatus as in claim 13 and wherein:

a. said radial squeezing force applying means includes a roller chain wrapped under tension at least partially around said spiral tube. 

1. An apparatus for continusouly producing spiral pipe from sheet material having longitudinal side edges having faces which are perpendicular to the plane of the sheet including: a. means for continuously deforming portions of said sheet material adjacent said longitudinal side edges thereof so as to bend said side edges downwardly toward the axis of the formed pipe and out of the normal plane of said sheet material, b. means for feeding said sheet material at an angle to the axis of the formed pipe, c. means for forming said sheet material into a spiral tube with said longitudinal side edges in parallel planes being moved into face to face abutting relationship, d. means for welding said abutting longitudinal edges into a seam, and e. means for reforming said deformed portions of said sheet material for providing a smooth continuous uninterrupted weld area.
 2. An apparatus as in claim 1 and wherein: a. said deforming means includes a roll couple.
 3. An apparatus as in claim 2 and wherein: a. said roll couple deforms said portions of said sheet by forming a rib therein.
 4. An apparatus as in claim 3 and wherein: a. said reforming means includes means for collapsing said rib.
 5. An apparatus as in claim 4 and wherein: a. said collapsing means includes a pair of cooperating roll members.
 6. An apparatus as in claim 5 and including: a. means for applying a radial squeezing force to said sheet material cooperatively with said forming means.
 7. An apparatus as in claim 6 and wherein: a. said deforming means is operative to deform each longitudinal side edge os said sheet material substantially simultaneously.
 8. An apparatus as in claim 7 and wherein: a. each of said roll members comprises a first and a second roll positioned inside of said spiral tube, and b. a third and a fourth roll positioned outside of said spiral tube.
 9. An apparatus as in claim 8 and wherein: a. said first roll cooperaTes with one of said third and fourth rolls for collapsing one of said ribs, and b. said second roll cooperates with the other of said third and fourth rolls for collapsing the other of said ribs.
 10. An apparatus as in claim 9 and wherein: a. said first, second, third and fourth rolls are water cooled.
 11. An apparatus as in claim 9 and wherein: a. said sheet material is substantially planar, and b. said angle is from about 28* to about 45*.
 12. An apparatus as in claim 11 and wherein: a. said radial squeezing force applying means includes a pair of rolls, and b. each of said rolls acting on said spiral tube at substantially diametrically opposed positions.
 13. An apparatus as in claim 9 and wherein: a. said sheet material is corrugated, and b. said angle is from about 45* to about 85*.
 14. An apparatus as in claim 13 and wherein: a. said radial squeezing force applying means includes a roller chain wrapped under tension at least partially around said spiral tube. 